dances of the men, among savages, excite the women, who watch them intently though unobtrusively, and are thus influenced in choosing their lovers. He was probably the first to insist that in man sexual selection has taken place mainly through the agency of dances, games, and festivals.[47] It is now clear, therefore, why the evacuation theory of the sexual impulse must necessarily be partial and inadequate. It leaves out of account the whole of the phenomena connected with tumescence, and those phenomena constitute the most prolonged, the most important, the most significant stage of the sexual process. It is during tumescence that the whole psychology of the sexual impulse is built up; it is as an incident arising during tumescence and influencing its course that we must probably regard nearly every sexual aberration. It is with the second stage of the sexual process, when the instinct of detumescence arises, that the analogy of evacuation can alone be called in. Even here, that analogy, though real, is not complete, the nervous element involved in detumescence being out of all proportion to the extent of the evacuation. The typical act of evacuation, however, is a nervous process, and when we bear this in mind we may see whatever truth the evacuation theory possesses. Beaunis classes the sexual impulse with the "needs of activity," but under this head he coordinates it with the "need of urination." That is to say, that both alike are nervous explosions. Micturition, like detumescence, is a convulsive act, and, like detumescence also, it is certainly connected with cerebral processes; thus in epilepsy the passage of urine which may occur (as in a girl described by Gowers with minor attacks during which it was emitted consciously, but involuntarily) is really a part of the process.[48]